c语言实现简单的udp传输（ c/s 模型）

/*client.c*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <arpa/inet.h>
#define MAXBUF 256
int main(int argc, char const *argv[])
{
int s = 0;
int n = 0;
int reuse = 1;
int port = 1987;
struct sockaddr_in srv;
char buf[MAXBUF] = {0};
/*解析参数*/
if (argc != 2)
{
printf("Usage:%s ServerIP\n", argv[0]);
return -1;
}

bzero(&srv, sizeof(srv));
srv.sin_family = PF_INET;
srv.sin_addr.s_addr = inet_addr(argv[1]);
srv.sin_port = htons(port);
/*创建 UDP 套节字*/
s = socket(AF_INET, SOCK_DGRAM, 0);
if(s<0){
perror("socket");
return -1;
}

while(1){
memset(buf, 0, MAXBUF);
/*读取用户输入到buf中*/
fgets(buf, MAXBUF, stdin);

/*通过套节字 s 向服务器发送数据*/
if ((n = sendto(s, buf, strlen(buf), 0, (struct sockaddr *) &srv, sizeof(struct sockaddr))) < 0)
{
perror("sendto");
return -1;
}else{
printf("send to %s(port=%d) len %d:%s\n", argv[1], port, n, buf);
}
}
}

/*server.c*/
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
#include <arpa/inet.h>

#define MAXBUF 256
int main(int argc, char const *argv[])
{
int s = 0;
int n = 0;
int reuse = 1;
int cli_len = sizeof(struct sockaddr);
int port = 1987;
char buf[MAXBUF] = {0};
struct sockaddr_in addr, cli;

/*初始化本地监听端口信息*/
bzero(&addr, sizeof(addr));
addr.sin_family = PF_INET;
addr.sin_addr.s_addr = INADDR_ANY;
addr.sin_port = htons(port);

/*创建UDP套节字*/
s = socket(AF_INET, SOCK_DGRAM, 0);
if (s<0)
{
perror("socket");
return -1;
}

/*允许端口复用*/
setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse));

/*绑定指定端口*/
if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0)
{
perror("bind");
return -1;
}

while(1){
memset(buf, 0, MAXBUF);
/*从套节字s中读取数据*/
n = recvfrom(s, buf, MAXBUF, 0, (struct sockaddr *)&cli, &cli_len);
if(n<0){
perror("recvfrom");
return -1;
}else{
printf("receive msg from %s(port=%d) len %d: %s\n",inet_ntoa(cli.sin_addr), port, n, buf);
}
}

return 0;
}

gcc client.c -o client
./client 127.0.0.1

gcc server.c -o server
./server